1// Copyright 2012 the V8 project authors. All rights reserved. 2// Redistribution and use in source and binary forms, with or without 3// modification, are permitted provided that the following conditions are 4// met: 5// 6// * Redistributions of source code must retain the above copyright 7// notice, this list of conditions and the following disclaimer. 8// * Redistributions in binary form must reproduce the above 9// copyright notice, this list of conditions and the following 10// disclaimer in the documentation and/or other materials provided 11// with the distribution. 12// * Neither the name of Google Inc. nor the names of its 13// contributors may be used to endorse or promote products derived 14// from this software without specific prior written permission. 15// 16// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 28#include "v8.h" 29 30#include "runtime-profiler.h" 31 32#include "assembler.h" 33#include "bootstrapper.h" 34#include "code-stubs.h" 35#include "compilation-cache.h" 36#include "execution.h" 37#include "full-codegen.h" 38#include "global-handles.h" 39#include "isolate-inl.h" 40#include "mark-compact.h" 41#include "platform.h" 42#include "scopeinfo.h" 43 44namespace v8 { 45namespace internal { 46 47 48// Optimization sampler constants. 49static const int kSamplerFrameCount = 2; 50 51// Constants for statistical profiler. 52static const int kSamplerFrameWeight[kSamplerFrameCount] = { 2, 1 }; 53 54static const int kSamplerTicksBetweenThresholdAdjustment = 32; 55 56static const int kSamplerThresholdInit = 3; 57static const int kSamplerThresholdMin = 1; 58static const int kSamplerThresholdDelta = 1; 59 60static const int kSamplerThresholdSizeFactorInit = 3; 61 62static const int kSizeLimit = 1500; 63 64// Constants for counter based profiler. 65 66// Number of times a function has to be seen on the stack before it is 67// optimized. 68static const int kProfilerTicksBeforeOptimization = 2; 69// If the function optimization was disabled due to high deoptimization count, 70// but the function is hot and has been seen on the stack this number of times, 71// then we try to reenable optimization for this function. 72static const int kProfilerTicksBeforeReenablingOptimization = 250; 73// If a function does not have enough type info (according to 74// FLAG_type_info_threshold), but has seen a huge number of ticks, 75// optimize it as it is. 76static const int kTicksWhenNotEnoughTypeInfo = 100; 77// We only have one byte to store the number of ticks. 78STATIC_ASSERT(kProfilerTicksBeforeOptimization < 256); 79STATIC_ASSERT(kProfilerTicksBeforeReenablingOptimization < 256); 80STATIC_ASSERT(kTicksWhenNotEnoughTypeInfo < 256); 81 82// Maximum size in bytes of generate code for a function to allow OSR. 83static const int kOSRCodeSizeAllowanceBase = 84 100 * FullCodeGenerator::kCodeSizeMultiplier; 85 86static const int kOSRCodeSizeAllowancePerTick = 87 3 * FullCodeGenerator::kCodeSizeMultiplier; 88 89// Maximum size in bytes of generated code for a function to be optimized 90// the very first time it is seen on the stack. 91static const int kMaxSizeEarlyOpt = 92 5 * FullCodeGenerator::kCodeSizeMultiplier; 93 94 95RuntimeProfiler::RuntimeProfiler(Isolate* isolate) 96 : isolate_(isolate), 97 sampler_threshold_(kSamplerThresholdInit), 98 sampler_threshold_size_factor_(kSamplerThresholdSizeFactorInit), 99 sampler_ticks_until_threshold_adjustment_( 100 kSamplerTicksBetweenThresholdAdjustment), 101 sampler_window_position_(0), 102 any_ic_changed_(false), 103 code_generated_(false) { 104 ClearSampleBuffer(); 105} 106 107 108static void GetICCounts(Code* shared_code, 109 int* ic_with_type_info_count, 110 int* ic_total_count, 111 int* percentage) { 112 *ic_total_count = 0; 113 *ic_with_type_info_count = 0; 114 Object* raw_info = shared_code->type_feedback_info(); 115 if (raw_info->IsTypeFeedbackInfo()) { 116 TypeFeedbackInfo* info = TypeFeedbackInfo::cast(raw_info); 117 *ic_with_type_info_count = info->ic_with_type_info_count(); 118 *ic_total_count = info->ic_total_count(); 119 } 120 *percentage = *ic_total_count > 0 121 ? 100 * *ic_with_type_info_count / *ic_total_count 122 : 100; 123} 124 125 126void RuntimeProfiler::Optimize(JSFunction* function, const char* reason) { 127 ASSERT(function->IsOptimizable()); 128 129 if (FLAG_trace_opt && function->PassesFilter(FLAG_hydrogen_filter)) { 130 PrintF("[marking "); 131 function->ShortPrint(); 132 PrintF(" for recompilation, reason: %s", reason); 133 if (FLAG_type_info_threshold > 0) { 134 int typeinfo, total, percentage; 135 GetICCounts(function->shared()->code(), &typeinfo, &total, &percentage); 136 PrintF(", ICs with typeinfo: %d/%d (%d%%)", typeinfo, total, percentage); 137 } 138 PrintF("]\n"); 139 } 140 141 142 if (isolate_->concurrent_recompilation_enabled() && 143 !isolate_->bootstrapper()->IsActive()) { 144 if (isolate_->concurrent_osr_enabled() && 145 isolate_->optimizing_compiler_thread()->IsQueuedForOSR(function)) { 146 // Do not attempt regular recompilation if we already queued this for OSR. 147 // TODO(yangguo): This is necessary so that we don't install optimized 148 // code on a function that is already optimized, since OSR and regular 149 // recompilation race. This goes away as soon as OSR becomes one-shot. 150 return; 151 } 152 ASSERT(!function->IsInRecompileQueue()); 153 function->MarkForConcurrentRecompilation(); 154 } else { 155 // The next call to the function will trigger optimization. 156 function->MarkForLazyRecompilation(); 157 } 158} 159 160 161void RuntimeProfiler::AttemptOnStackReplacement(JSFunction* function) { 162 // See AlwaysFullCompiler (in compiler.cc) comment on why we need 163 // Debug::has_break_points(). 164 if (!FLAG_use_osr || 165 isolate_->DebuggerHasBreakPoints() || 166 function->IsBuiltin()) { 167 return; 168 } 169 170 SharedFunctionInfo* shared = function->shared(); 171 // If the code is not optimizable, don't try OSR. 172 if (!shared->code()->optimizable()) return; 173 174 // We are not prepared to do OSR for a function that already has an 175 // allocated arguments object. The optimized code would bypass it for 176 // arguments accesses, which is unsound. Don't try OSR. 177 if (shared->uses_arguments()) return; 178 179 // We're using on-stack replacement: patch the unoptimized code so that 180 // any back edge in any unoptimized frame will trigger on-stack 181 // replacement for that frame. 182 if (FLAG_trace_osr) { 183 PrintF("[OSR - patching back edges in "); 184 function->PrintName(); 185 PrintF("]\n"); 186 } 187 188 BackEdgeTable::Patch(isolate_, shared->code()); 189} 190 191 192void RuntimeProfiler::ClearSampleBuffer() { 193 memset(sampler_window_, 0, sizeof(sampler_window_)); 194 memset(sampler_window_weight_, 0, sizeof(sampler_window_weight_)); 195} 196 197 198int RuntimeProfiler::LookupSample(JSFunction* function) { 199 int weight = 0; 200 for (int i = 0; i < kSamplerWindowSize; i++) { 201 Object* sample = sampler_window_[i]; 202 if (sample != NULL) { 203 bool fits = FLAG_lookup_sample_by_shared 204 ? (function->shared() == JSFunction::cast(sample)->shared()) 205 : (function == JSFunction::cast(sample)); 206 if (fits) { 207 weight += sampler_window_weight_[i]; 208 } 209 } 210 } 211 return weight; 212} 213 214 215void RuntimeProfiler::AddSample(JSFunction* function, int weight) { 216 ASSERT(IsPowerOf2(kSamplerWindowSize)); 217 sampler_window_[sampler_window_position_] = function; 218 sampler_window_weight_[sampler_window_position_] = weight; 219 sampler_window_position_ = (sampler_window_position_ + 1) & 220 (kSamplerWindowSize - 1); 221} 222 223 224void RuntimeProfiler::OptimizeNow() { 225 HandleScope scope(isolate_); 226 227 if (isolate_->DebuggerHasBreakPoints()) return; 228 229 DisallowHeapAllocation no_gc; 230 231 // Run through the JavaScript frames and collect them. If we already 232 // have a sample of the function, we mark it for optimizations 233 // (eagerly or lazily). 234 JSFunction* samples[kSamplerFrameCount]; 235 int sample_count = 0; 236 int frame_count = 0; 237 int frame_count_limit = FLAG_watch_ic_patching ? FLAG_frame_count 238 : kSamplerFrameCount; 239 for (JavaScriptFrameIterator it(isolate_); 240 frame_count++ < frame_count_limit && !it.done(); 241 it.Advance()) { 242 JavaScriptFrame* frame = it.frame(); 243 JSFunction* function = frame->function(); 244 245 if (!FLAG_watch_ic_patching) { 246 // Adjust threshold each time we have processed 247 // a certain number of ticks. 248 if (sampler_ticks_until_threshold_adjustment_ > 0) { 249 sampler_ticks_until_threshold_adjustment_--; 250 if (sampler_ticks_until_threshold_adjustment_ <= 0) { 251 // If the threshold is not already at the minimum 252 // modify and reset the ticks until next adjustment. 253 if (sampler_threshold_ > kSamplerThresholdMin) { 254 sampler_threshold_ -= kSamplerThresholdDelta; 255 sampler_ticks_until_threshold_adjustment_ = 256 kSamplerTicksBetweenThresholdAdjustment; 257 } 258 } 259 } 260 } 261 262 SharedFunctionInfo* shared = function->shared(); 263 Code* shared_code = shared->code(); 264 265 if (shared_code->kind() != Code::FUNCTION) continue; 266 if (function->IsInRecompileQueue()) continue; 267 268 if (FLAG_always_osr && 269 shared_code->allow_osr_at_loop_nesting_level() == 0) { 270 // Testing mode: always try an OSR compile for every function. 271 for (int i = 0; i < Code::kMaxLoopNestingMarker; i++) { 272 // TODO(titzer): fix AttemptOnStackReplacement to avoid this dumb loop. 273 shared_code->set_allow_osr_at_loop_nesting_level(i); 274 AttemptOnStackReplacement(function); 275 } 276 // Fall through and do a normal optimized compile as well. 277 } else if (!frame->is_optimized() && 278 (function->IsMarkedForLazyRecompilation() || 279 function->IsMarkedForConcurrentRecompilation() || 280 function->IsOptimized())) { 281 // Attempt OSR if we are still running unoptimized code even though the 282 // the function has long been marked or even already been optimized. 283 int ticks = shared_code->profiler_ticks(); 284 int allowance = kOSRCodeSizeAllowanceBase + 285 ticks * kOSRCodeSizeAllowancePerTick; 286 if (shared_code->CodeSize() > allowance) { 287 if (ticks < 255) shared_code->set_profiler_ticks(ticks + 1); 288 } else { 289 int nesting = shared_code->allow_osr_at_loop_nesting_level(); 290 if (nesting < Code::kMaxLoopNestingMarker) { 291 int new_nesting = nesting + 1; 292 shared_code->set_allow_osr_at_loop_nesting_level(new_nesting); 293 AttemptOnStackReplacement(function); 294 } 295 } 296 continue; 297 } 298 299 // Only record top-level code on top of the execution stack and 300 // avoid optimizing excessively large scripts since top-level code 301 // will be executed only once. 302 const int kMaxToplevelSourceSize = 10 * 1024; 303 if (shared->is_toplevel() && 304 (frame_count > 1 || shared->SourceSize() > kMaxToplevelSourceSize)) { 305 continue; 306 } 307 308 // Do not record non-optimizable functions. 309 if (shared->optimization_disabled()) { 310 if (shared->deopt_count() >= FLAG_max_opt_count) { 311 // If optimization was disabled due to many deoptimizations, 312 // then check if the function is hot and try to reenable optimization. 313 int ticks = shared_code->profiler_ticks(); 314 if (ticks >= kProfilerTicksBeforeReenablingOptimization) { 315 shared_code->set_profiler_ticks(0); 316 shared->TryReenableOptimization(); 317 } else { 318 shared_code->set_profiler_ticks(ticks + 1); 319 } 320 } 321 continue; 322 } 323 if (!function->IsOptimizable()) continue; 324 325 if (FLAG_watch_ic_patching) { 326 int ticks = shared_code->profiler_ticks(); 327 328 if (ticks >= kProfilerTicksBeforeOptimization) { 329 int typeinfo, total, percentage; 330 GetICCounts(shared_code, &typeinfo, &total, &percentage); 331 if (percentage >= FLAG_type_info_threshold) { 332 // If this particular function hasn't had any ICs patched for enough 333 // ticks, optimize it now. 334 Optimize(function, "hot and stable"); 335 } else if (ticks >= kTicksWhenNotEnoughTypeInfo) { 336 Optimize(function, "not much type info but very hot"); 337 } else { 338 shared_code->set_profiler_ticks(ticks + 1); 339 if (FLAG_trace_opt_verbose) { 340 PrintF("[not yet optimizing "); 341 function->PrintName(); 342 PrintF(", not enough type info: %d/%d (%d%%)]\n", 343 typeinfo, total, percentage); 344 } 345 } 346 } else if (!any_ic_changed_ && 347 shared_code->instruction_size() < kMaxSizeEarlyOpt) { 348 // If no IC was patched since the last tick and this function is very 349 // small, optimistically optimize it now. 350 Optimize(function, "small function"); 351 } else { 352 shared_code->set_profiler_ticks(ticks + 1); 353 } 354 } else { // !FLAG_watch_ic_patching 355 samples[sample_count++] = function; 356 357 int function_size = function->shared()->SourceSize(); 358 int threshold_size_factor = (function_size > kSizeLimit) 359 ? sampler_threshold_size_factor_ 360 : 1; 361 362 int threshold = sampler_threshold_ * threshold_size_factor; 363 364 if (LookupSample(function) >= threshold) { 365 Optimize(function, "sampler window lookup"); 366 } 367 } 368 } 369 if (FLAG_watch_ic_patching) { 370 any_ic_changed_ = false; 371 } else { // !FLAG_watch_ic_patching 372 // Add the collected functions as samples. It's important not to do 373 // this as part of collecting them because this will interfere with 374 // the sample lookup in case of recursive functions. 375 for (int i = 0; i < sample_count; i++) { 376 AddSample(samples[i], kSamplerFrameWeight[i]); 377 } 378 } 379} 380 381 382void RuntimeProfiler::SetUp() { 383 if (!FLAG_watch_ic_patching) { 384 ClearSampleBuffer(); 385 } 386} 387 388 389void RuntimeProfiler::Reset() { 390 if (!FLAG_watch_ic_patching) { 391 sampler_threshold_ = kSamplerThresholdInit; 392 sampler_threshold_size_factor_ = kSamplerThresholdSizeFactorInit; 393 sampler_ticks_until_threshold_adjustment_ = 394 kSamplerTicksBetweenThresholdAdjustment; 395 } 396} 397 398 399void RuntimeProfiler::TearDown() { 400 // Nothing to do. 401} 402 403 404// Update the pointers in the sampler window after a GC. 405void RuntimeProfiler::UpdateSamplesAfterScavenge() { 406 for (int i = 0; i < kSamplerWindowSize; i++) { 407 Object* function = sampler_window_[i]; 408 if (function != NULL && isolate_->heap()->InNewSpace(function)) { 409 MapWord map_word = HeapObject::cast(function)->map_word(); 410 if (map_word.IsForwardingAddress()) { 411 sampler_window_[i] = map_word.ToForwardingAddress(); 412 } else { 413 sampler_window_[i] = NULL; 414 } 415 } 416 } 417} 418 419 420void RuntimeProfiler::RemoveDeadSamples() { 421 for (int i = 0; i < kSamplerWindowSize; i++) { 422 Object* function = sampler_window_[i]; 423 if (function != NULL && 424 !Marking::MarkBitFrom(HeapObject::cast(function)).Get()) { 425 sampler_window_[i] = NULL; 426 } 427 } 428} 429 430 431void RuntimeProfiler::UpdateSamplesAfterCompact(ObjectVisitor* visitor) { 432 for (int i = 0; i < kSamplerWindowSize; i++) { 433 visitor->VisitPointer(&sampler_window_[i]); 434 } 435} 436 437 438} } // namespace v8::internal 439